Proximal gastric response to small intestinal nutrients is abnormal in mechanically ventilated critically ill patients

Abstract

Aim: To determine the response of the proximal stomach to small intestinal nutrients in critically ill patients.

Methods: Proximal gastric motility was measured in 13 critically ill patients (49.3 +/- 4.7 years) and 12 healthy volunteers (27.7 +/- 2.9 years) using a barostat technique. Recordings were performed at baseline, during a 60-min intra-duodenal infusion of Ensure (2 kcal/min), and for 2 h following the infusion. Minimum distending pressure (MDP), intra-bag volume and fundic wave activity were determined.

Results: The MDP was higher in patients (11.7 +/- 1.1 vs 7.8 +/- 0.7 mmHg; P < 0.01). Baseline intra-bag volumes were similar in the 2 groups. In healthy subjects, a 'bimodal' proximal gastric volume response was observed. In patients, the initial increase in proximal gastric volume was small and delayed, but eventually reached a maximal volume similar to that of healthy subjects. In healthy subjects, the proximal gastric volume rapidly returned to baseline level after nutrient infusion (median 18 min). In contrast, the recovery of volume to baseline was delayed in critically ill patients (median 106 min). In 6 patients, the volume had not returned to baseline level 2 hours after nutrient infusion. In patients, fundic volume waves were less frequent (P < 0.05) and had lower amplitude (P < 0.001), compared to healthy subjects.

Conclusion: In critical illness, proximal gastric motor responses to small intestinal nutrient stimulation are abnormal.

Figure 1

Changes in proximal gastric volume during the 2 kcal/min infusion, in healthy (dotted line, n = 12) and critically ill (solid line, n = 13) subjects. Data are mean ± SE. ^aP < 0.05 vs healthy subjects.

Figure 2

Changes in proximal gastric volume from baseline at the 10^th minute and at peak level during the nutrient infusion, in healthy (open circle, n = 12) and critically ill (closed circle, n = 13) subjects. ^cP < 0.001 vs healthy subjects.

Figure 3

Time course for the proximal gastric volume to return to baseline level after nutrient stimulation, in healthy (dotted line, n = 12) and critically ill (solid line n = 13) subjects. Data are mean ± SE.

Figure 4

Fundic slow volume waves (per 10 min) during the 2 kcal/min nutrient infusion, in healthy (open bar, n = 12) and critically ill (closed bar, n = 13) subjects. Data are mean ± SE. ^aP < 0.05 vs healthy subjects.